Preventing and reversing advanced glycosylation endproducts

ABSTRACT

The present invention relates to compositions and methods for inhibiting and reversing nonenzymatic cross-linking (protein aging). Accordingly, a composition is disclosed which comprises a thiazolium compound capable of inhibiting, and to some extent reversing, the formation of advanced glycosylation endproducts of target proteins by reacting with the carbonyl moiety of the early glycosylation product of such target proteins formed by their initial glycosylation. The method comprises contacting the target protein with the composition. Both industrial and therapeutic applications for the invention are envisioned, as food spoilage and animal protein aging can be treated. A novel immunoassay for detection of the reversal of the nonenzymatic crosslinking is also disclosed.

BACKGROUND OF THE INVENTION

The present invention relates generally to the aging of proteinsresulting from their reaction with glucose and other reducing sugars andmore particularly to the inhibition of the reaction of nonenzymaticallyglycosylated proteins and the reversal of the often resultant formationof advanced glycosylation (glycation) endproducts and cross-links.

The reaction between glucose and proteins has been known for some time.Its earlier manifestation was in the appearance of brown pigments duringthe cooking of food, which was identified by Maillard in 1912, whoobserved that glucose or other reducing sugars react with amino acids toform adducts that undergo a series of dehydrations and rearrangements toform stable brown pigments. Further studies have suggested that storedand heat treated foods undergo nonenzymatic browning as a result of thereaction between glucose and the polypeptide chain, and that theproteins are resultingly cross-linked and correspondingly exhibitdecreased bioavailability.

This reaction between reducing sugars and food proteins was found tohave its parallel in vivo. Thus, the nonenzymatic reaction betweenglucose and the free amino groups on proteins to form a stable,1-deoxyketosyl adduct, known as the Amadori product, has been shown tooccur with hemoglobin, wherein a rearrangement of the amino terminal ofthe beta-chain of hemoglobin by reaction with glucose, forms the adductknown as hemoglobin Alc. The reaction has also been found to occur witha variety of other body proteins, such as lens crystallins, collagen andnerve proteins. See Bucala et al., “Advanced Glycosylation; Chemistry,Biology, and Implications for Diabetes and Aging” in Advances inPharmacology, Vol. 23. pp. 1-34, Academic Press (1992).

Moreover, brown pigments with spectral and fluorescent propertiessimilar to those of late-stage Maillard products have also been observedin vivo in association with several long-lived proteins, such as lensproteins and collagen from aged individuals. An age-related linearincrease in pigment was observed in human dura collagen between the agesof 20 to 90 years. Interestingly, the aging of collagen can be mimickedin vitro by the cross-linking induced by glucose; and the capture ofother proteins and the formation of adducts by collagen, also noted, istheorized to occur by a cross-linking reaction, and is believed toaccount for the observed accumulation of albumin and antibodies inkidney basement membrane.

In U.S. Pat No. 4,758,583, a method and associated agents were disclosedthat served to inhibit the formation of advanced glycosylationendproducts by reacting with an early glycosylation product that resultsfrom the original reaction between the target protein and glucose.Accordingly, inhibition was postulated to take place as the reactionbetween the inhibitor and the early glycosylation product appeared tointerrupt the subsequent reaction of the glycosylated protein withadditional protein material to form the cross-linked late-stage product.One of the agents identified as an inhibitor was aminoguanidine, and theresults of further testing have borne out its efficacy in this regard.

While the success that has been achieved with aminoguanidine and similarcompounds is promising, a need continues to exist to identify anddevelop additional inhibitors that broaden the availability and perhapsthe scope of this potential activity and its diagnostic and therapeuticutility. A further need exists to find agents which not only inhibitthis reaction and its consequences, but agents capable of reversing thealready formed advanced glycosylation endproducts, thereby reversing theresultant effects thereof.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method and compositions aredisclosed for the inhibition and reversal of the advanced glycosylationof proteins (protein aging). In particular, the compositions compriseagents for inhibiting the formation of and reversing the pre-formedadvanced glycosylation (glycation) endproducts and cross-linking. Theagents are members of the class of compounds known as thiazoliums.Advanced glycation endproducts and cross-linking caused by otherreactive sugars present in vivo or in foodstuffs, including ribose,galactose and fructose would also be prevented and reversed by themethods and compositions of the present invention.

The agents comprise thiazolium compounds having the following structuralformula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower) alkyl, lower alkyl, or R¹ and R² togetherwith their ring carbons may be an aromatic fused, ring;

Z is hydrogen or an amino group;

Y is amino, a group of the formula

wherein R is a lower alkyl, alkoxy, hydroxy, amino or aryl group;

or a group of the formula —CH₂R′

wherein R′ is hydrogen, or a lower alkyl, lower alkynyl, or aryl group;

X is a halide, tosylate, methanesulfonate or mesitylenesulfonate ion;

and mixtures thereof, and a carrier therefor.

The compounds, and their compositions, utilized in this invention appearto react with an early glycosylation product thereby preventing the samefrom later forming the advanced glycosylation end products which lead toprotein cross-links, and thereby, to protein aging, and further, reactwith already formed advanced glycosylation end products to reduce theamount of such products.

The present invention also relates to a method for inhibiting proteinaging by contacting the initially glycosylated protein at the stage ofthe early glycosylation product with a quantity of one or more of theagents of the present invention, or a composition containing the same,and to a method for breaking the already formed advanced glycosylationend products to reduce the amount of such products. In the instancewhere the present method has industrial application, one or more of theagents may be applied to the proteins in question, either byintroduction into a mixture of the same in the instance of a proteinextract, or by application or introduction into foodstuffs containingthe protein or proteins, all to prevent premature aging and spoilage ofthe particular foodstuffs, and to reverse the effects of already formedadvanced glycosylation end products.

The ability to inhibit the formation of advanced glycosylationendproducts, and to reverse the already formed advanced glycosylationproducts in the body carries with it significant implications in allapplications where protein aging is a serious detriment. Thus, in thearea of food technology, the retardation of food spoilage would conferan obvious economic and social benefit by making certain foods ofmarginal stability less perishable and therefore more available forconsumers. Spoilage would be reduced as would the expense of inspection,removal, and replacement, and the extended availability of the foodscould aid in stabilizing their price in the marketplace. Similarly, inother industrial applications where the perishability of proteins is aproblem, the admixture of the agents of the present invention incompositions containing such proteins would facilitate the extendeduseful life of the same. Presently used food preservatives anddiscoloration preventatives such as sulfur dioxide, known to causetoxicity including allergy and asthma in animals, can be replaced withcompounds such as those described herein.

The present method has particular therapeutic application as theMaillard process acutely affects several of the significant proteinmasses in the body, among them collagen, elastin, lens proteins, and thekidney glomerular basement membranes. These proteins deteriorate bothwith age (hence the application of the term “protein aging”) and as aconsequence of diabetes. Accordingly, the ability to either retard orsubstantially inhibit the formation of advanced glycosylationendproducts, and to reduce the amount of already formed advancedglycosylation endproducts in the body carries the promise of treatmentfor diabetes and, of course, improving the quality and, perhaps,duration of animal and human life.

The present agents are also useful in the area of personal appearanceand hygiene, as they prevent, and reverse, the staining of teeth bycationic anti-microbial agents with anti-plaque properties, such aschlorhexidine.

The invention additionally comprises a novel analytic method for thedetermination of the “breaking” or reversal of the formation ofnon-enzymatic endproducts.

Accordingly, it is a principal object of the present invention toprovide a method for inhibiting the formation of advanced glycosylationendproducts and extensive cross-linking of proteins, and a method ofreversing the already formed advanced glycosylation endproducts andcross-links, that occur as an ultimate consequence of the reaction ofthe proteins with glucose and other reactive sugars, by correspondinglyinhibiting the formation of advanced glycosylation endproducts, andreversing the advanced glycosylation that has previously occurred.

It is a further object of the present invention to provide a method asaforesaid which is characterized by a reaction with an initiallyglycosylated protein identified as an early glycosylation product.

It is a further object of the present invention to provide a method asaforesaid which prevents the rearrangement and cross-linking of the saidearly glycosylation products to form the said advanced glycosylationendproducts.

It is a yet further object of the present invention to provide agentscapable of participating in the reaction with the said earlyglycosylation products in the method as aforesaid.

It is a yet further object of the present invention to provide agentswhich break or reverse the advanced glycosylation endproducts formed asa consequence of the aforesaid advanced glycosylation reaction sequence.

It is a still further object of the present invention to providetherapeutic methods of treating the adverse consequences of proteinaging by resort to the aforesaid method and agent.

It is a still further object of the present invention to provide amethod of inhibiting, and reversing, the discoloration of teeth byresort to the aforesaid method and agents.

It is a still further object of the present invention to providecompositions, including pharmaceutical compositions, all incorporatingthe agents of the present invention.

It is still further object of the present invention to provide novelcompounds, as well as processes for their preparation, for use in themethods and compositions of the present invention.

It is a still further object of the present invention to provide a novelimmunoassay which can be utilized to detect compounds having the abilityto “break” or reverse the formation of non-enzymatic glycosylationendproducts.

Other objects and advantages will become apparent to those skilled inthe art from a consideration of the ensuring description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, agents, compositions includingpharmaceutical compositions containing said agents and associatedmethods have been developed which are believed to inhibit the formationof advanced glycosylation endproducts in a number of target proteinsexisting in both animals and plant material, and to reverse the alreadyformed advanced glycosylation endproducts. In particular, the inventionrelates to a composition which may contain one or more agents comprisingthiamine compounds having the structural formula

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower) alkyl, lower acyloxy(lower)alkyl, loweralkyl, or R¹ and R² together with their ring carbons may be an aromaticfused ring;

Z is hydrogen or an amino group;

Y is hydrogen, or a group of the formula

wherein R is a lower alkyl, alkoxy, hydroxy, amino or aryl group;

or a group of the formula —CH₂R′

wherein R′ is hydrogen, or a lower alkyl, lower alkynyl, or aryl group;

X is a halide, tosylate, methanesulfonate or mesitylenesulfonate ion;

and mixtures thereof, and a carrier therefor.

The lower alkyl groups referred to above contain 1-6 carbon atoms andinclude methyl, ethyl, propyl, butyl, pentyl, hexyl, and thecorresponding branched-chain isomers thereof. The lower alkynyl groupscontain from 2 to 6 carbon atoms. Similarly, the lower alkoxy groupscontain from 1 to 6 carbon atoms, and include methoxy, ethoxy, propoxy,butoxy, pentoxy, and hexoxy, and the corresponding branched-chainisomers thereof. These groups are optionally substituted by one or morehalo, hydroxy, amino or lower alkylamino groups.

The lower acyloxy(lower)alkyl groups encompassed by the above formulainclude those wherein the acyloxy portion contain from 2 to 6 carbonatoms and the lower alkyl portion contains from 1 to 6 carbon atoms.Typical acyloxy portions are those such as acetoxy or ethanoyloxy,propanoyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, and thecorresponding branched chain isomers thereof. Typical lower alkylportions are as described hereinabove. The aryl groups encompassed bythe above formula are those containing 6-10 carbon atoms, such as phenyland lower alkyl substituted-phenyl e.g., tolyl and xylyl, and areoptionally substituted by 1-2 halo, hydroxy, lower alkoxy or di(lower)alkylamino groups. Preferred aryl groups are phenyl, methoxyphenyt and4-bromophenyl groups.

The halo atoms in the above formula may be fluoro, chloro, bromo oriodo.

For the purposes of this invention, the compounds of formula (I) areformed as biologically and pharmaceutically acceptable salts. Usefulsalt forms are the halides, particularly the bromide and chloride,tosylate, methanesulfonate, and mesitylenesulfonate salts. Other relatedsalts can be formed using similarly non-toxic, and biologically andpharmaceutically acceptable anions.

Of the compounds encompassed by Formula I, certain substituents arepreferred. For instance, the compounds wherein R₁ or R₂ are lower alkylgroups are preferred. Also highly preferred are the compounds wherein Yis a 2-phenyl-2-oxoethyl or a 2-[4′-bromophenyl]-2-oxoethyl group.

Representative compounds of the present invention are:

3-aminothiazolium mesitylenesulfonate;

3-amino-4,5-dimethylaminothiazolium mesitylenesulfonate;

2,3-diaminothiazolinium mesitylenesulfonate;

3-(2-methoxy-2-oxoethyl)-thiazolium bromide;

3-(2-methoxy-2-oxoethyl)-4,5-dimethylthiazolium bromide;

3-(2-methoxy-2-oxoethyl)-4-methylthiazolium bromide:

3-(2-phenyl-2-oxoethyl)-4-methylthizolium bromide;

3-(2-phenyl-2-oxoethyl)-4,5-dimethylthiazolium bromide;

3-amino-4-methylthiazolium mesitylenesulfonate;

3-(2-methoxy-2-oxoethyl)-5-methylthiazolium bromide;

3-(3-(2-phenyl-2-oxoethyl)-5-methylthiazolium bromide;

3-[2-(4′-bromophenyl)-2-oxoethyl]thiazolium bromide;

3-[2-(4′-bromophenyl)-2-oxoethyl]-4-methylthiazolium bromide;

3-[2-(4′-bromophenyl)-2-oxoethyl]-5-methylthiazolium bromide;

3-[2-(4′bromophenyl)-2-oxoethyl]-4,5-dimethylthiazolium bromide;

3-(2-methoxy-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl) thiazolium bromide;

3-(2-phenyl-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl) thiazolium bromide;

3-[2-(4′-bromophenyl)-2-oxoethyl]-4-methyl-5-(2-hydroxyethyl)thiazoliumbromide;

3,4-dimethyl-5-(2-hydroxyethyl)thiazolium iodide;

3-ethyl-5-(2-hydroxyethyl)-4-methylthiazolium bromide;

3-benzyl-5-(2-hydroxyethyl)-4-methylthiazolium chloride;

3-(2-methoxy-2-oxoethyl)benzothiazolium bromide;

3-(2-phenyl-2-oxoethyl)benzothiazolium bromide;

3-[2-(4′bromophenyl)-2-oxoethyl]benzothiazolium bromide;

3-(carboxymethyl)benzothiazolium bromide;

2,3-(diamino)benzothiazolium mesitylenesulfonate;

3-(2-amino-2-oxoethyl)thiazolium bromide;

3-(2-amino-2-oxoethyl)-4-methylthiazolium bromide;

3-(2-amino-2-oxoethyl)-5-methylthiazolium bromide;

3-(2-amino-2-oxoethyl)4,5-dimethylthiazolium bromide;

3-(2-amino-2- oxoethyl) benzothiazolium bromide;

3-(2-amino-2- oxoethyl) 4-methyl-5-(2-hydroxyethyl) thiazolium bromide;

3-amino-5-(2-hydroxyethyl)-4-methylthiazolium mesitylenesulfonate;

3-(2-methyl-2-oxoethyl)thiazolium chloride;

3-amino-4-methyl-5-(2-acetoxyethyl)thiazolium mesitylenesulfonate;

3-(2-phenyl-2-oxoethyl)thiazolium bromide;

3-(2-methoxy-2-oxoethyl)-4-methyl-5-(2-acetoxyethyl) thiazolium bromide;

3-(2-amino-2-oxoethyl)-4-methyl-5-(2-acetoxyethyl) thiazolium bromide;

2-amino-3-(2-methoxy-2-oxoethyl)thiazolium bromide;

2-amino-3-(2-methoxy-2-oxoethyl)benzothiazolium bromide;

2-amino-3-(2-amino-2-oxoethyl)thiazolium bromide;

2-amino-3-(2-amino-2-oxoethyl)benzothiazolium bromide;

3-[2-(4′-methoxyphenyl)-2-oxoethyl]-thiazolinium bromide;

3-[2-(2′,4′-dimethoxyphenyl)-2-oxoethyl]-thiazolinium bromide;

3-[2-(4′-fluorophenyl)-2-oxoethyl]-thiazolinium bromide;

3-[2-(2′,4′-difluorophenyl)-2-oxoethyl]-thiazolinium bromide;

3-[2-(4′-diethylaminophenyl)-2-oxoethyl]-thiazolinium bromide;

3-propargyl-thiazolinium bromide;

3-propargyl-4-methylthiazolinium bromide;

3-propargyl-5-methylthiazolinium bromide;

3-propargyl-4,5-dimethylthiazolinium bromide; and

3-propargyl-4-methyl-5-(2-hydroxyethyl)-thiazolinium bromide.

Certain of the compounds represented by Formula I are novel compoundswhich represent a further embodiment of the present invention. Thesecompounds are represented by the formula

wherein Y and Z are both amino groups and R¹ and R² are as hereinbeforedefined; and X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.

The above compounds are capable of inhibiting the formation of advancedglycosylation endproducts on target proteins, as well as being capableof breaking or reversing already formed advanced glycosylationendproducts on such proteins. The cross-linking of the protein to formthe advanced glycosylation endproduct contributes to the entrapment ofother proteins and results in the development in vivo of conditions suchas reduced elasticity and wrinkling of the skin, certain kidneydiseases, atherosclerosis, osteoarthritis and the like. Similarly, plantmaterial that undergoes nonenzymatic browning deteriorates and, in thecase of foodstuffs, become spoiled or toughened and, consequently,inedible. Thus, the compounds employed in accordance with this inventioninhibit this late-stage Maillard effect and intervene in the deleteriouschanges described above, and reverse the level of the advancedglycosylation endproducts already present in the protein material.

The rationale of the present invention is to use agents which block, aswell as reverse, the post-glycosylation step, i.e., the formation offluorescent chromophores, the presence of which chromophores isassociated with, and leads to adverse sequelae of diabetic complicationsand aging. An ideal agent would prevent the formation of the chromophoreand its associated cross-links of proteins to proteins and trapping ofproteins on the other proteins, such as occurs in arteries and in thekidney, and reverse the level of such cross-link formation alreadypresent.

The chemical nature of the early glycosylation products with which thecompounds of the present invention are believed to react may vary, andaccordingly the term “early glycosylation product(s)” as used herein isintended to include any and all such variations within its scope. Forexample, early glycosylation products with carbonyl moieties that areinvolved in the formation of advanced glycosylation endproducts, andthat may be blocked by reaction with the compounds of the presentinvention, have been postulated. In one embodiment, it is envisionedthat the early glycosylation product may comprise the reactive carbonylmoieties of Amadori products or their further condensation, dehydrationand/or rearrangement products, which may condense to form advancedglycosylation endproducts. In another scenario, reactive carbonylcompounds, containing one or more carbonyl moieties (such asglycolaldehyde, glyceraldehyde or 3-deoxyglucosone) may form from thecleavage of Amadori or other early glycosylation endproducts, and bysubsequent reactions with an amine or Amadori product, may form carbonylcontaining advanced glycosylation products such asalkylformylglycosylpyrroles.

Several investigators have studied the mechanism of advancedglycosylation product formation. In vitro studies by Eble et al.,(1983), “Nonenzymatic Glucosylaton and Glucose-dependent Cross-linkingof Protein”, J. Biol. Chem., 258: 9406-9412, concerned the cross-linkingof glycosylated protein with nonglycosylated protein in the absence ofglucose. Eble et al. sought to elucidate the mechanism of the Maillardreaction and accordingly conducted controlled initial glycosylation ofRNAase as a model system, which was then examined under varyingconditions. In one aspect, the glycosylated protein material wasisolated and placed in a glucose-free environment and thereby observedto determine the extent of cross-linking.

Eble et al. thereby observed that cross-linking continued to occur notonly with the glycosylated protein but with non-glycosylated proteins aswell. One of the observations noted by Eble et al. was that the reactionbetween glycosylated protein and the protein material appeared to occurat the location on the amino acid side-chain of the protein.Confirmatory experimentation conducted by Eble et al. in this connectiondemonstrated that free lysine would compete with the lysine on RNAasefor the binding of glycosylated protein. Thus, it might be inferred fromthese data that lysine may serve as an inhibitor of advancedglycosylation; however, this conclusion and the underlying observationsleading to it should be taken in the relatively limited context of themodel system prepared and examined by Eble et al. Clearly, Eble et al.does not appreciate, nor is there a suggestion therein, of thediscoveries that underlie the present invention, with respect to theinhibition of advanced glycosylation of proteins both in vitro and invivo.

The experiments of Eble et al. do not suggest the reactive cleavageproduct mechanism or any other mechanism in the in vivo formation ofadvanced glycosylation endproducts in which glucose is always present.In fact, other investigators support this mechanism to explain theformation of advanced glycosylated endproducts in vivo (see for exampleHayase et al, J. Biol. Chem., 263, pp. 3758-3764 (1989); Sell andMonnier, J. Biol. Chem. 264, pp. 21597-21602 (1989); Oimomi et al.,Agric. Biol. Chem., .53(6): 1727-1728 (1989); and Diabetes Research andClinical Practice, 6: 311-313 (1989). Accordingly, the use of lysine asan inhibitor in the Eble et al. model system has no bearing upon theutility of the compounds of the present invention in the inhibition ofadvanced glycosylated endproducts formation in the presence of glucosein vivo, and the amelioration of complications of diabetes and aging.

The present invention likewise relates to methods for inhibiting theformation of advanced glycosylation endproducts, and reversing the levelof already formed advanced glycosylation endproducts, which comprisecontacting the target proteins with a composition of the presentinvention. In the instance where the target proteins are contained infoodstuffs, whether of plant or animal origin, these foodstuffs couldhave applied to them by various conventional means a compositioncontaining the present agents.

In the food industry, sulfites were found years ago to inhibit theMaillard reaction and are commonly used in processed and stored foods.Recently, however, sulfites in food have been implicated in severe andeven fatal reactions in asthmatics. As a consequence, the sulfitetreatment of fresh fruits and vegetables has been banned. The mechanismfor the allergic reaction is not known. Accordingly, the presentcompositions and agents offer a nontoxic alternative to sulfites in thetreatment of foods in this manner.

As is apparent from a discussion of the environment of the presentinvention, the present methods and compositions hold the promise forarresting, and to some extent reversing, the aging of key proteins bothin animals and plants, and concomitantly, conferring both economic andmedical benefits as a result thereof. In the instance of foodstuffs, theadministration of the present composition holds the promise forretarding food spoilage thereby making foodstuffs of increased shelflife and greater availability to consumers. Replacement ofcurrently-used preservatives, such as sulfur dioxide known to causeallergies and asthma in humans, with non-toxic, biocompatible compoundsis a further advantage of the present invention.

The therapeutic implications of the present invention relate to thearrest, and to some extent, the reversal of the aging process which has,as indicated earlier, been identified in the aging of key proteins byadvanced glycosylation and cross-linking. Thus, body proteins, andparticularly structural body proteins, such as collagen, elastin, lensproteins, nerve proteins, kidney glomerular basement membranes and otherextravascular matrix components would all benefit in their longevity andoperation from the practice of the present invention. The presentinvention thus reduces the incidence of pathologies involving theentrapment of proteins by cross-linked target proteins, such asretinopathy, cataracts, diabetic kidney disease, glomerulosclerosis,peripheral vascular disease, arteriosclerosis obliterans, peripheralneuropathy, stroke, hypertension, atherosclerosis, osteoarthritis,periarticular rigidity, loss of elasticity and wrinkling of skin,stiffening of joints, glomerulonephritis, etc. Likewise, all of theseconditions are in evidence in patients afflicted with diabetes mellitus.Thus, the present therapeutic method is relevant to treatment of thenoted conditions in patients either of advanced age or those sufferingfrom one of the mentioned pathologies.

Protein cross-linking through advanced glycosylation product formationcan decrease solubility of structural proteins such as collagen invessel walls and can also trap serum proteins, such as lipoproteins tothe collagen. Also, this may result in increased permeability of theendothelium and consequently covalent trapping of extravasated plasmaproteins in subendothelial matrix, and reduction in susceptibility ofboth plasma and matrix proteins to physiologic degradation by enzymes.For these reasons, the progressive occlusion of diabetic vessels inducedby chronic hyperglycemia has been hypothesized to result from excessiveformation of glucose-derived cross-links. Such diabetic microvascularchanges and microvascular occlusion can be effectively prevented andreversed by chemical inhibition and reversal of the advancedglycosylation product formation utilizing a composition and the methodsof the present invention.

Studies indicate that the development of chronic diabetic damage intarget organs is primarily linked to hyperglycemia so that tightmetabolic control would delay or even prevent end-organ damage. SeeNicholls et al., Lab. Invest., 60, No. 4, p. 486 (1989), which discussesthe effects of islet isografting and aminoguanidine in murine diabeticnephropathy. These studies further evidence that aminoguanidinediminishes aortic wall protein cross-linking in diabetic rats andconfirm earlier studies by Brownlee et al., Science, 232, pp. 1629-1632(1986) to this additional target organ of complication of diabetes.Also, an additional study showed the reduction of immunoglobulintrapping in the kidney by aminoguanidine (Brownlee et al., Diabetes, 35Suppl. 1, p. 42A (1986)).

Further evidence in the streptozotocin-diabetic rat model thataminoguanidine administration intervenes in the development of diabeticnephropathy was presented by Brownlee et al., 1988, supra, with regardto morphologic changes in the kidney which are hallmarks of diabeticrenal disease. These investigators reported that the increasedglomerular basement membrane thickness, a major structural abnormalitycharacteristic of diabetic renal disease, was prevented withaminoguanidine.

Taken together, these data strongly suggest that inhibition and reversalof the formation of advanced glycosylation endproducts (AGEs), by theteaching of the present invention, may prevent, as well as to someextent reverse late, as well as early, structural lesions due todiabetes, as well as changes during aging caused by the formation ofAGEs.

Diabetes-induced changes in the deformability of red blood cells,leading to more rigid cell membranes, is another manifestation ofcross-linking and aminoguanidine has been shown to prevent it in vivo.In such studies, New Zealand White rabbits, with induced, long-termdiabetes are used to study the effects of a test compound on red bloodcell (RBC) deformability (df). The test compound is administered at arate of 100 mg/kg by oral gavage to diabetic rabbits.

A further consequence of diabetes is the hyperglycemia-induced matrixbone differentiation resulting in decreased bone formation usuallyassociated with chronic diabetes. In animal models, diabetes reducesmatrix-induced bone differentiation by 70%.

In the instance where the compositions of the present invention areutilized for in vivo or therapeutic purposes, it may be noted that thecompounds or agents used therein are biocompatible. Pharmaceuticalcompositions may be prepared with a therapeutically effective quantityof the agents or compounds of the present invention and may include apharmaceutically acceptable carrier, selected from known materialsutilized for this purpose. Such compositions may be prepared in avariety of forms, depending on the method of administration. Also,various pharmaceutically acceptable addition salts of the compounds ofFormula I may be utilized.

A liquid form would be utilized in the instance where administration isby intravenous, intramuscular or intraperitoneal injection. Whenappropriate, solid dosage forms such as tablets, capsules, or liquiddosage formulations such as solutions and suspensions, etc., may beprepared for oral administration. For topical or dermal application tothe skin or eye, a solution, a lotion or ointment may be formulated withthe agent in a suitable vehicle such as water, ethanol, propyleneglycol, perhaps including a carrier to aid in penetration into the skinor eye. For example, a topical preparation could include up to about 10%of the compound of Formula I. Other suitable forms for administration toother body tissues are also contemplated.

In the instance where the present method has therapeutic application,the animal host intended for treatment may have administered to it aquantity of one or more of the agents, in a suitable pharmaceuticalform. Administration may be accomplished by known techniques, such asoral, topical and parenteral techniques such as intradermal,subcutaneous, intravenous or intraperitoneal injection, as well as byother conventional means. Administration of the agents may take placeover an extended period of time at a dosage level of, for example, up toabout 30 mg/kg.

As noted earlier, the invention also extends to a method of inhibitingand reversing the discoloration of teeth resulting from nonenzymaticbrowning in the oral cavity which comprises administration to a subjectin need of such therapy an amount effective to inhibit and reverse theformation of advanced glycosylation endproducts of a compositioncomprising an agent of structural Formula I.

The nonenzymatic browning reaction which occurs in the oral cavityresults in the discoloration of teeth. Presently used anti-plaque agentsaccelerate this nonenzymatic browning reaction and further the stainingof the teeth. Recently, a class of cationic anti-microbial agents withremarkable anti-plaque properties have been formulated in oral rinsesfor regular use to kill bacteria in the mouth. These agents, thecationic antiseptics, include such agents as alexidine, cetyl pyridiniumchloride, chlorhexidine gluconate, hexetidine, and benzalkoniumchloride.

Tooth staining by chlorhexidine and other anti-plaque agents apparentlyresults from the enhancement of the Maillard reaction. Nordbo, J. Dent.Res., 58, p. 1429 (1979) reported that chlorhexidine and benzalkoniumchloride catalyze browning reactions in vitro. Chlorhexidine added tomixtures containing a sugar derivative and a source of amino groupsunderwent increased color formation, attributed to the Maillardreaction. It is also known that use of chlorhexidine results in anincreased dental pellicle. Nordbo proposed that chlorhexidine resultedin tooth staining in two ways: first, by increasing formation ofpellicle which contains more amino groups, and secondly, by catalysis ofthe Maillard reaction leading to colored products.

In accordance with this method, the compounds of Formula I areformulated into compositions adapted for use in the oral cavity.Particularly suitable formulations are oral rinses and toothpastesincorporating the active agent.

In the practice of this invention, conventional formulating techniquesare utilized with nontoxic, pharmaceutically acceptable carrierstypically utilized in the amounts and combinations that are well-knownfor the formulation of such oral rinses and toothpastes.

The agent of Formula I is formulated in compositions in an amounteffective to inhibit and reverse the formation of advanced glycosylationendproducts. This amount will, of course, vary with the particular agentbeing utilized and the particular dosage form, but typically is in therange of 0.01% to 1.0%, by weight, of the particular formulation.

The compounds encompassed by Formula I are conveniently prepared bychemical syntheses well-known in the art. Certain of the compoundsencompassed by Formula I are well-known compounds readily available fromchemical supply houses and/or are preparable by synthetic methodsspecifically published therefor. For instance,3,4-dimethyl-5-(2-hydroxyethyl)thiazolium iodide;3-ethyl-5-(2-hydroxyethyl)-4-methylthiazolium bromide;3-benzyl-5-(2-hydroxyethyl)-4-methylthiazolium chloride; and3-(carboxymethyl)benzothiazolium bromide are obtainable from AldrichChem. Co.

Compounds described in the chemical and patent literature or directlypreparable by methods described therein and encompassed by Formula I arethose such as 3-(2-phenyl-2-oxoethyl)-4-methylthiazolium bromide and3-(2-phenyl-2-oxoethyl)-4-methylthiazolium bromide [Potts et al. J. Org.Chem, 41, pp. 187-191 (1976)].

Certain of the compounds of formula (I) are novel compounds, notheretofore known in the art. These compounds are those represented bythe formula Ia

wherein Y and Z are both amino groups and R¹ and R² are independentlyselected from the group consisting of hydrogen, hydroxy(lower)alkyl,lower alkyl, or R¹ and R² together with their ring carbons may be anaromatic fused ring; and X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion. Other novel compounds are those of formula Iwherein Y is a lower alkynylmethyl group or a 2-amino-2-oxoethyl group.

The compounds of formula I wherein Y is a group of the formula

wherein R is a lower alkyl, alkoxy, hydroxy, amino or aryl group;

or a group of the formula —CH₂R′

wherein R′ is hydrogen, or a lower alkyl, lower alkynyl or aryl group;

X is a halide, tosylate, methanesulfonate or mesitylenesulfonate ion;

can be prepared according to the methods described in Potts et al., J.Org. Chem., 41, 187 (1976); and Potts et al., J. Org. Chem., 42, 1648(1977), or as shown in Scheme I below.

wherein R¹, R², Z, and R are as hereinabove defined, and X is a halogenatom.

In reaction Scheme I, the appropriate substituted thiazole compound offormula II wherein R¹, R² and Z are as hereinbefore defined, is reactedwith the appropriate halo compound of formula III wherein R and X are ashereinbefore defined, to afford the desired compound of formula Iwherein R¹, R², Z, R and X are as hereinbefore defined.

Typically, this reaction is conducted at reflux temperatures for timesof about 1-3 hours. Typically, a polar solvent such as ethanol isutilized for the conduct of the reaction.

The compounds of formula I wherein Y is an amino group can be preparedaccording to the methods described in Tamura et al., Synthesis, 1(1977), or as shown below in Scheme II.

wherein R¹, R² and Z are as defined hereinabove.

In the reaction shown in Scheme II, typically conducted in an anhydrouspolar solvent at room temperatures, typical reaction temperatures rangefrom room temperature to reflux, and typical times vary from 1 to about4 hours. This reaction affords the mesitylene sulfonate, which can thenbe optionally converted to other thiazolium salts by typical exchangereactions.

The present invention also involves a novel sandwich enzyme immunoassayused to ascertain the ability of test compounds to “break” or reversealready formed advanced glycosylation endproducts by detecting thebreaking of AGE (Advanced glycosylation endproduct) moieties fromAGE-crosslinked protein. This assay comprises:

a) incubation of AGE-modified bovine serum albumin (AGE-BSA) oncollagen-coated wells of microtiter plates for a period of 2-6 hours ata temperature of 37° C.;

b) washing of the wells with PBS-Tween;

c) application of the test compounds to the washed wells of step b;

d) incubation of the test compounds applied to the washed wells for anadditional 12-24 hours at a temperature of about 37° C.; and

e) detection of the AGE-breaking using an antibody raised againstAGE-ribonuclease or cross-link breaking with an antibody against BSA.

The following examples are illustrative of the invention.

EXAMPLE 1 3-(2-Methoxy-2-oxoethyl)thiazolium bromide

Thiazole, (850 mg, 10 mmol), methyl bromoacetate (1.52, 10 mmol) andabsolute ethanol (50 ml) were refluxed for 2 hours. On cooling, the saltseparated and was recrystallized from absolute ethanol to give the titlecompound (1.59 g), m.p. 189°-190° C. (dec).

EXAMPLE 2 3-Amino-4,5-dimethylthiazolium mesitylenesulfonate

An ice cold solution of the 4,5-dimethyl thiazole (2.26 g, 20 mmol) indry dichloromethane (15 ml) was treated dropwise with a solution ofo-mesitylenesulfonylhydroxyamine (4.3 g, 20 mmol) in dry dichloromethane(15 ml). After stirring for 2 hours at room temperature, anhydrous ether(10 ml) was added. On cooling, colorless needles of the title product,3-amino-4,5-dimethyl-thiazolium mesitylenesulfonate, separated (3.48 g),m.p. 165°-168° C.

EXAMPLE 3

Using the procedures described above in Examples 1 and 2, the followingcompounds are prepared.

(1) 3-amino-thiazolium mesitylenesulfonate, m.p. 102°-104° C.

(2) 2,3 -diamino-thiazolium mesitylenesulfonate, m.p. 173°-175° C.(dec).

(3) 3-(2-methoxy-2-oxoethyl)-4,5-dimethylthiazolium bromide. m.p.184°-185°-200° C. (dec).

(4) 3-(2-methoxy-2-oxoethyl)-4-methylthiazolium bromide, m.p. 149°-151°C. (dec).

(5) 3-(2-phenyl-2-oxoethyl)-4-methylthiazolium bromide, m.p. 218°-220°C. (dec).

(6) 3-(2-phenyl-2-oxoethyl)-4,5-dimethylthiazolium bromide, m.p.212°-213° C. (dec).

(7) 3-amino-4-methyl-thiazolium mesitylene sulfonate, m.p. 143°-144° C.

(8) 3-(2-methoxy-2-oxoethyl)-5-methyl-thiazolium bromide, m.p. 193°-194°C. (dec).

(9) 3-(2-phenyl-2-oxoethyl)-5-methyl-thiazolium bromide, m.p. 193°-194°C.

(10) 3-(2-[4¹-bromophenyl]-2-oxoethyl)-thiazolium bromide, m.p.269°-270° C. (dec).

(11) 3-(2-[4¹-bromophenyl]-2-oxoethyl)-4-methyl-thiazolium bromide, m.p.248°-249° C. (dec).

(12) 3-(2-[4¹-bromophenyl]-2-oxoethyl)-5-methyl-thiazolium bromide, m.p.216°-217° C.

(13) 3-(2-[4¹-bromophenyl]-2-oxoethyl)-4,5-dimethylthiazolium bromide,m.p. 223°-224° C. (dec).

(14) 3-(2-methoxy-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)-thiazoliumbromide, m.p. 137°-138° C.

(15) 3-(2-phenyl-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)-thiazoliumbromide, m.p. 180°-181° C.

(16)3-(2-[4¹-bromophenyl]-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)thiazoliumbromide, m.p. 251°-252° C. (dec).

(17) 3,4-dimethyl-5-(2-hydroxyethyl)-thiazolium iodide, m.p. 85°-87° C.

(18) 3-ethyl-5-(2-hydroxyethyl)-4-methyl thiazolium bromide, m.p.84°-85° C.

(19) 3-benzyl-5-(2-hydroxyethyl)-4-methyl thiazolium chloride, m.p.144°-146° C.

(20) 3-(2-methoxy-2-oxoethyl)-benzothiazolium bromide, m.p. 144°-145° C.(dec).

(21) 3-(2-phenyl-2-oxoethyl)-benzothiazolium bromide, m.p. 240°-241° C.(dec).

(22) 3-(2-[4¹-bromophenyl)-2-oxoethyl)-benzothiazolium bromide, m.p.261°-262° C. (dec).

(23) 3-(carboxymethyl)-benzothiazolium bromide m.p. 250° C. (dec).

(24) 2,3-diamino-benzothiazolium mesitylenesulfonate, m.p. 212°-214° C.(dec).

(25) 3-(2-amino-2-oxoethyl)-thiazolium bromide, m.p. 205°-206° C.

(26) 3-(2-amino-2-oxoethyl)-4-methyl-thiazolium bromide, m.p. 220°-222°C.

(27) 3-(2-amino-2-oxoethyl)-5-methyl-thiazolium bromide, m.p. 179°-180°C.

(28) 3-(2-amino-2-oxoethyl)-4,5-dimethyl-thiazolium bromide, m.p.147°-148° C.

(29) 3-(2-amino-2-oxoethyl)-benzothiazolium bromide, m.p. 222°-223° C.

(30) 3-(2-amino-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)thiazoliumbromide, m.p. 182°-183° C.

(31) 3-amino-5-(2-hydroxyethyl)-4-methyl-thiazolium mesitylenesulfonate,m.p. 94°-95° C. (dec).

(32) 3-(2-methyl-2-oxoethyl)thiazolium chloride, m.p. 178°-179° C.

(33) 3-amino-4-methyl-5-(2-acetoxyethyl)thiazolium mesitylenesulfonate,m.p. 118°-120° C.

(34) 3-(2-phenyl-2-oxoethyl)thiazolium bromide, m.p. 217°-218° C.

(35) 3-(2-methoxy-2-oxoethyl)-4-methyl-5-(2-acetoxyethyl)thiazoliumbromide, m.p. 217°-218° C.

(36) 3-(2-amino-2-oxoethyl)-4-methyl-5-(2-acetoxyethyl)thiazoliumbromide, m.p. 233°-234° C.

(37) 2-amino-3-(2-methoxy-2-oxoethyl)thiazolium bromide, m.p. 191°-192°C.

(38) 2-amino-3-(2-methoxy-2-oxoethyl)benzothiazolium bromide, m.p.236°-237° C.

(39) 2-amino-3-(2-amino-2-oxoethyl)thiazolium bromide, m.p. 209°-210° C.

(40) 2-amino-3-(2-amino-2-oxoethyl)benzothiazolium bromide, m.p.234°-235° C.

EXAMPLE 4

The following method was used to evaluate the ability of the compoundsof the present invention to inhibit the cross-linking of glycated bovineserum albumin (AGE-BSA) to the rat tail tendon collagen coated 96-wellplate.

The AGE-BSA was prepared by incubating BSA at a concentration of 200 mgper ml with 200 mM glucose in 0.4M sodium phosphate buffer, pH 7.4 at37° C. for 12 weeks. The glycated BSA was then extensively dialyzedagainst phosphate buffer solution (PBS) for 48 hours with additional 5times buffer exchanges. The rat tail tendon collagen coated plate wasblocked first with 300 μl of superbloc blocking buffer (Pierce #37515X)for one hour. The blocking solution was removed from the wells bywashing the plate twice with PBS-Tween 20 solution (0.05% Tween 20)using a NUNC-multiprobe or Dynatec ELISA-plate washer. Cross-linking ofAGE-BSA (1 to 10 μg per well depending on the batch of AGE-BSA) to rattail tendon collagen coated plate was performed with and without thetesting compound dissolved in PBS buffer at pH 7.4 at the desiredconcentrations by the addition of 50 μl each of the AGE-BSA diluted inPBS or in the testing compound at 37° C. for 4 hours. The unbrowned BSAin PBS buffer with or without testing compound were added to theseparate wells as the blanks. The un-cross-linked AGE-BSA was thenremoved by washing the wells three times with PBS-Tween buffer. Thecross-linked AGE-BSA to the tail tendon coated plate was thenquantitated by the polyclonal antibody raised against AGE-RNase. After aone-hour incubation period, AGE antibody was removed by washing 4 timeswith PBS-Tween.

The bound AGE antibody was then detected with the addition ofhorseradish peroxidase-conjugated secondary antibody—goat anti-rabbitimmunoglobulin and incubation for 30 minutes. The substrate of2,2-azino-di(3-ethylbenzthiazoline sulfonic acid) (ABTS chromogen)(Zymed #00-2011) was added. The reaction was allowed for an additional15 minutes and the absorbance was read at 410 nm in a Dynatech platereader.

The % inhibition of each test compound was calculated as follows.

% inhibition={[Optical density (without compound)−optical density (withcompound)]/optical density (without compound)]}×100%

The IC₅₀ values or the inhibition at various concentrations by testcompounds is as follows:

Relative IC₅₀ Inhibition Test Compound (mM) (at 10 mM)3-amino-4,5-dimethylaminothiazolium 69% mesitylenesulfonate2,3-diaminothiazolinium mesitylenesulfonate 27%3-(2-methoxy-2-oxoethyl)-thiazolium bromide 0.1383-(2-methoxy-2-oxoethyl)-4,5- 0.138 dimethylthiazolium bromide3-(2-methoxy-2-oxoethyl)-4-methylthiazolium 58% bromide3-(2-phenyl-2-oxoethyl)-4-methylthizolium 10.3 bromide3-(2-phenyl-2-oxoethyl)-4,5-di- 48.5 methylthiazolium bromide3-amino-4-methylthiazolium 46% mesitylenesulfonate3-(2-methoxy-2-oxoethyl)-5-methylthiazolium 0.073 bromide3-(3-(2-phenyl-2-oxoethyl)-5-methylthiazolium 13.89 bromide3-[2-(4′-bromophenyl)-2-oxoethyl]-4- 37% methylthiazolium bromide3-[2-(4′bromophenyl)-2-oxoethyl]-4,5- 2.92 dimethylthiazolium bromide3-(2-methoxy-2-oxoethyl)-4-methyl-5-(2- 38% hydroxyethyl)thiazoliumbromide 3-(2-phenyl-2-oxoethyl)-4-methyl-5-(2- 36%hydroxyethyl)thiazolium bromide3-[2-(4′-bromophenyl)-2-oxoethyl]-4-methyl-5- 4.51(2-hydroxyethyl)thiazolium bromide3-(2-methoxy-2-oxoethyl)benzothiazolium 35% bromide3-(carboxymethyl)benzothiazolium bromide 16%2,3-(diamino)benzothiazolium 0.0749 mesitylenesulfonate3-(2-amino-2-oxoethyl)thiazolium bromide 0.2263-(2-amino-2-oxoethyl)-4-methylthiazolium 0.116 bromide3-(2-amino-2-oxoethyl)-5-methylthiazolium 0.0289 bromide3-(2-amino-2-oxoethyl)4,5-dimethylthiazolium 0.338 bromide3-(2-amino-2-oxoethyl)benzothia- 0.618 zolium bromide3-(2-amino-2-oxoethyl)4-methyl-5-(2- 1.256 hydroxyethyl)thiazoliumbromide 3-amino-5-(2-hydroxyethyl)-4-methylthia- 0.026 zoliummesitylenesulfonate 3-(2-phenyl-2-oxoethyl)thiazolium bromide 34%

The above experiments suggest that this type of drug therapy may havebenefit in reducing the pathology associated with the advancedglycosylation of proteins and the formation of cross-links betweenproteins and other macromolecules. Drug therapy may be used to preventthe increased trapping and cross-linking of proteins that occurs indiabetes and aging which leads to sequelae such as retinal damage, andextra-vascularly, damage to tendons, ligaments and other joints. Thistherapy might retard atherosclerosis and connective tissue changes thatoccur with diabetes and aging. Both topical, oral, and parenteral routesof administration to provide therapy locally and systemically arecontemplated.

EXAMPLE 5

In order to ascertain the ability of the compounds of the instantinvention to “break” or reverse already formed advanced glycosylationendproducts, a novel sandwich enzyme immunoassay was developed whichdetects breaking of AGE (Advanced glycosylation endproduct) moietiesfrom AGE-crosslinked protein. The assay utilizes collagen-coated 96 willmicrotiter plates that are obtained commercially. AGE-modified protein(AGE-BSA) is incubated on the collagen-coated wells for four hours, iswashed off the wells with PBS-Tween and the test compounds are added.Following an incubation period of 16 hours (37° C.) AGE-breaking isdetected using an antibody raised against AGE-ribonuclease or with anantibody against BSA. Positive results in this assay indicate compoundsthat are capable of reducing the amount of AGE-BSA previouslycrosslinked to the collagen. Details of the assay are as follows:

MATERIALS Immunochemicals and Chemicals

Bovine Serum Albumin (Type V), (BSA) Calbiochem Dextrose Superbloc,Pierce, Inc. Rabbit anti(AGE-RNAse) Rabbit anti-Bovine Serum AlbuminHorseradish Peroxidase (HRP)-Goat-anti-rabbit), Zymed HRP substratebuffer, Zymed ABTS chromogen, Zymed Phosphate Buffer Saline Tween 20,Sigma

Equipment

ELISA Plate Washer, Dynatech ELISA Plate Reader, Dynatech PrecisionWater Bath Corning digital pH meter

Glassware and Plasticware

Finneppette Multichannel Pipettor, Baxter Eppendorf pipettes, BaxterEppendorf repeater pipette, Baxter Pipetter tips for Finneppetter,Baxter Pipetter tips for Eppendorf, Baxter Glass test tubes, 13×100 mm;Baxter Mylar Sealing Tape for 96 well plates, Corning Biocoat CellwareRat Tail Collagen Type-1 coated 96-well plates, Collaborative BiomedicalProducts

METHODS Preparation of Solutions and Buffers

1. AGE-BSA stock solutions were prepared as follows. Sodium phosphatebuffer (0.4M) was prepared by dissolving 6 grams of monobasic sodiumphosphate in 100 ml of distilled water, 7 grams of dibasic sodiumphosphate (0.4M) in 100 ml of distilled water and adjusting the pH ofthe dibasic solution to 7.4 with the monobasic solution. Sodium azide(0.02 grams) was added per 100 ml volume to inhibit bacterial growth.The BSA solution was prepared as follows: 400 mg of Type V BSA (bovineserum albumin) was added for each ml of sodium phosphate buffer (above).A 400 mM glucose solution was prepared by dissolving 72 grams ofdextrose in 100 ml of sodium phosphate buffer (above). The BSA andglucose solutions were mixed 1:1 and incubated at 37° C. for 12 weeks.The pH of the incubation mixture was monitored weekly and adjusted to pH7.4 if necessary. After 12 weeks, the AGE-BSA solution was dialyzedagainst PBS for 48 hours with four buffer changes, each at a 1:500 ratioof solution to dialysis buffer. Protein concentration was determined bythe micro-Lowry method. The AGE-BSA stock solution was aliquoted andstored at −20° C. Dilute solutions of AGE-BSA were unstable when storedat −20° C.

2. Working solutions for crosslinking and breaking studies were preparedas follows. Test compounds were dissolved in PBS and the pH was adjustedto pH 7.4 if necessary. AGE-BSA stock solution was diluted in PBS tomeasure maximum crosslinking and in the inhibitor solution for testinginhibitory activity of compounds. The concentration of AGE-BSA necessaryto achieve the optimum sensitivity was determined by initial titrationof each lot of AGE-BSA.

3. Wash buffer (“PBS-Tween”) was prepared as follows. PBS was preparedby dissolving the following salts in one liter of distilled water: NaCl,8 grams; KCl, 0.2 gram, KH₂PO₄. 1.15 grams; NaN₃, 0.2 gram. Tween-20 wasadded to a final concentration of 0.05% (vol/vol).

4. Substrates for detection of secondary antibody binding were preparedby diluting the HRP substrate buffer 1:10 in distilled water and mixingwith ABTS chromogen 1:50 just prior to use.

Assay Procedures

1. Biocoat plates were blocked With 300 μl of “Superbloc”. Plates wereblocked for one hour at room temperature and were washed with PBS-Tweenthree times with the Dynatech platewasher before addition of testreagents.

2. Each experiment was set up in the following manner. The first threewells of the Biocoat plate were used for the reagent blank. Fiftymicroliters of solutions containing either AGE-BSA alone or incombination with the test compounds: and corresponding blanks with BSAwere added to wells in triplicate. The plate was incubated at 37° C. forfour hours and washed with PBS-Tween three times. Fifty microliters ofPBS was added to the control wells and 50 μl of the test “AGE Breaker”compounds was added to the test wells. The plate was incubated overnight(approximately 16 hours) with the test “AGE breaker” compound, followedbywashing in PBS before addition of primary antibody (below).

3. Each lot of primary antibody (anti-AGE RNase or anti-BSA) was testedfor optimum binding capacity in this assay by preparing serial dilutions(1:500 to 1:2000) and plating 50 μl of each dilution in the wells ofBiocoat plates. Optimum primary antibody was determined from saturationkinetics. Fifty microliters of primary antibody of appropriate dilution,determined by initial titration, was added and incubated for one hour atroom temperature. The plate was then washed with PBS-Tween.

4. Plates were incubated with the secondary antibody, HRP-(Goatanti-rabbit), which was diluted 1:4000 in PBS and used as the finalsecondary antibody. The incubation was performed at room temperature forthirty minutes.

5. Detection of maximum crosslinking and breaking of AGE crosslinkingwas performed as follows. HRP substrate (100 ul) was added to each wellof the plate and was incubated at 37° C. for fifteen minutes. Readingswere taken in the Dynatech ELISA-plate reader. The sample filter was setto “1” and the reference filter was set to “5”.

STANDARD OPERATING PROCEDURE Preliminary Steps

1. Titrate each new lot of AGE-BSA preparation as described in Table 4and determine the optimum AGE-BSA concentration for the ELISA assay fromsaturation kinetics.

2 At the beginning of the day, flush the plate washer head with hotwater, rinse with distilled water and 50% ethanol. Fill the bufferreservoir of the plate washer with PBS-Tween (0.05%) and purge thesystem three times before use.

3. Prepare an assay template for setting up the experiment as describedunder “Assay Setup”, #2, below.

Assay Setup

1. Warm Superbloc reagent to 37° C. Add 300 μl of Superbloc to each wellof the Biocoat plate and let stand for sixty minutes at 37° C. Wash thewells three times with PBS-Tween (0.05%). Turn the plate 180 degrees andrepeat this wash cycle.

2. Dilute the AGE-BSA in PBS so that 50 μl of the diluted sample willcontain the amount of AGE-BSA necessary for minimum crosslinking andinhibition by pimagedine (aminoguanidine), as determined by initialtitration described above. Prepare negative controls by dissolvingnon-browned BSA in PBS at the same concentration as the AGE-BSA. Add 50μl of AGE-BSA or BSA to each well which correspond to the “AGE-BSA” and“BSA” labels on the template.

3. Dissolve the test compounds in PBS at 30 mM concentration forpreliminary evaluation. The pH must be checked and adjusted to 7.4 whennecessary. Pretreat the collagen-coated plates with AGE-BSA to obtainmaximum crosslinking. Prepare negative controls for inhibitionexperiments by dissolving BSA in the inhibition solution at the sameprotein concentration as that used for AGE-BSA. Add 50 μl of AGE-BSA orBSA in the inhibitor solutions to the wells which correspond to“ALT#+AGE-BSA” and to “ALT# blank”, respectively, on the template.Incubate the plate at 37° C. for four hours. Following covalent bindingof AGE-BSA to the plates, wash the plates with PBS-Tween in preparationof the detection reaction (below).

4. Binding of primary antibody to the Biocoat plates is carried out asfollows. At the end of the four hour incubation, the wells are washedwith PBS-Tween. Appropriate dilutions (as determined by initialtitration) of the rabbit-anti-AGE-RNase or rabbit-anti-BSA antibodieswere prepared in PBS, and 50 μl is added to each well and the plate isallowed to stand at room temperature for sixty minutes.

6. Color development was carried out as follows. Plates are washed as inStep 4 above. Dilute the HRP-substrate buffer 1:10 in water. Add 200 μlof ABTS solution, mix well and add 100 μl of this reagent to each well.Incubate the plate at 37° C. for fifteen minutes. Read the opticaldensity at 410 nm with the sample filter set to “1” and the referencefilter set to “5” on the Dynatech ELISA plate reader. Calculate thepercent inhibition by the compound as described above. Compounds whichare found to reduce the amount of immunoreactivity are considered to betherapeutically useful insofar as they reverse and reduce the levels ofadvanced glycosylation endproducts.

IC₅₀ (mM) % Inhibition Anti-AGE/ Anti-AGE/Anti-BSA Test CompoundAnti-BSA (at mM) 3-aminothiazolium 0.05/3.0 mesitylenesulfonate3-amino-4,5-dimethylamino- 46%/ND (10) thiazolium mesitylenesulfonate2,3-diaminothiazolinium 0.0006/0.18 mesitylenesulfonate3-(2-methoxy-2-oxoethyl)- 38%/41% (30) thiazolium bromide3-(2-methoxy-2-oxoethyl)-4,5- 50%/30% (30) dimethylthiazolium bromide3-(2-methoxy-2-oxoethyl)-4- 54%/41% (30) methylthiazolium bromide3-(2-phenyl-2-oxoethyl)-4- 0.23/0.30 methylthizolium bromide3-(2-phenyl-2-oxoethyl)-4,5- 56%/ND (30) dimethylthiazolium bromide3-amino-4-methylthiazolium 55%/ND (30) mesitylenesulfonate3-(2-methoxy-2-oxoethyl)-5- 72%/27% (30) methyl)thiazolium bromide3-[2-(4′-bromophenyl)-2- 76%/25% (30) oxoethyl]thiazolium bromide3-(2-phenyl-2-oxoethyl)-4- 14.3/112.0 methyl-5-(2-hydroxyethyl)thia-zolium bromide 3-benzyl-5-(2-hydroxyethyl)-4- 0.42/0.55 methylthiazoliumchloride 3-(2-methoxy-2-oxoethyl)- 1.20/25.9 benzothiazolium bromide3-(carboxymethyl)benzothia- 63.7%/17.9% (30) zolium bromide2,3-(diamino)benzothiazolium 75%/35% (30) mesitylenesulfonate3-(2-amino-2-oxoethyl)-4- 4.70/38.6 methylthiazolium bromide3-(2-amino-2-oxoethyl)-4,5-di- 69%/75% (30) methylthiazolium bromide3-(2-amino-2-oxoethyl)benzo- 0.14/0.52 thiazolium bromide3-(2-amino-2-oxoethyl)-4- 0.012/0.120 methyl-5-(2-hydroxyethyl)-thiazolium bromide 3-amino-5-(2-hydroxyethyl)-4- 0.18/0.50methylthiazolium mesitylene- sulfonate 3-(2-methyl-2-oxoethyl)-0.000036/0.260 thiazolium chloride 3-(2-phenyl-2-oxoethyl)- 0.020/0.014thiazolium bromide

EXAMPLE 6

mg/tablet Compound of Formula I 50 Starch 50 Mannitol 75 Magnesiumstearate 2 Stearic acid 5

The compound, a portion of the starch and the lactose are combined andwet granulated with starch paste. The wet granulation is placed on traysand allowed to dry overnight at a temperature of 45° C. The driedgranulation is comminuted in a comminutor to a particle size ofapproximately 20 mesh. Magnesium stearate, stearic acid and the balanceof the starch are added and the entire mix blended prior to compressionon a suitable tablet press. The tablets are compressed at a weight of232 mg. using a {fraction (11/32)}″ punch with a hardness of 4 kg. Thesetablets will disintegrate within a half hour according to the methoddescribed in USP XVI.

EXAMPLE 7

Lotion mg/g Compound of Formula I 1.0 Ethyl alcohol 400.0 Polyethyleneglycol 400 300.0 Hydroxypropyl cellulose 5.0 Propylene glycol to make1.0 g

EXAMPLE 8

Oral Rinse Compound of Formula I: 1.4% Chlorhexidine gluconate 0.12%Ethanol 11.6% Sodium saccharin 0.15% FD&C Blue No. 1 0.001% Peppermintoil 0.5% Glycerine 10.0% Tween 60 0.3% Water to 100%

EXAMPLE 9

Toothpaste Compound of Formula I: 5.5% Sorbitol, 70% in water 25% Sodiumsaccharin 0.15% Sodium lauryl sulfate 1.75% Carbopol 934, 6% dispersionin 15% Oil of Spearmint 1.0% Sodium hydroxide, 50% in water 0.76%Dibasic calcium phosphate dehydrate 45% Water to 100%

EXAMPLE 10

To further study the ability of inhibitors of nonenzymatic browning toprevent the discoloration of protein on a surface, such as that whichoccurs on the tooth surface, the following surface browning experimentis performed. As a substitute for a pellicle-covered tooth surface,unexposed and developed photographic paper is used to provide a fixedprotein (gelatin, i.e., collagen) surface on a paper backing. Fivemillimeter circles are punched and immersed for one week at 50° C. in asolution of 100 mM glucose-6-phosphate in a 0.5M phosphate buffer, pH7.4, containing 3 mM sodium azide. Glucose-6-phosphate is a sugarcapable of participating in nonenzymatic browning at a more rapid ratethan glucose. In addition to the glucose-6-phosphate, chlorhexidineand/or a compound of Formula I are included. After incubation, thegelatin/paper disks are rinsed with water, observed for brown color, andphotographed.

Incubation of the disks in glucose-6-phosphate alone shows slight browncolor versus disks soaked in buffer alone. Inclusion of chlorhexidine(in the form of Peridex®at a final concentration of 0.04% chlorhexidine)shows significant browning. Addition of a compound of Formula I to thechlorhexidine completely inhibits browning of the gelatin, as doesinclusion of a compound of Formula I in the absence of chlorhexidine.

The slight brown color formed by the action of glucose-6-phosphate onthe gelatin surface alone and its prevention by a compound of Formula Idemonstrates the utility of the present invention in preventingnonenzymatic browning of tooth surfaces. The enhanced browning in thepresence of chlorhexidine and its prevention with a compound of FormulaI demonstrates the utility of the present invention in preventing theanti-plaque agent-enhanced nonenzymatic browning which occurs withchlorhexidine.

This invention may be embodied in other forms or carried out in otherways without departing from the spirit or essential characteristicsthereof. The present disclosure is therefore to be considered as in allrespects illustrative and not restrictive, the scope of the inventionbeing indicated by the appended claims, and all changes which comewithin the meaning and range of equivalency are intended to be embracedtherein.

What is claimed is:
 1. A composition for inhibiting the advancedglycosylation of a target protein in the oral cavity comprising aneffective amount of a compound one or more compounds selected from thegroup consisting of compounds of the formula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower) alkyl, lower acyloxy(lower)alkyl, or loweralkyl, or R₁ and R₂ together with their ring carbons may be form anaromatic fused ring; Z is hydrogen or an amino group; Y is hydrogen, ora group of the formula —CH₂C(═O)—R wherein R is a lower alkyl, loweralkoxy, hydroxy, amino or aryl group, and wherein, when R is aryl, atleast one of R¹ and R ² is other than hydrogen and R ¹ and R ² are notpart of a un-substituted fused phenyl ring; or a group of the formula—CH₂R′ wherein R′ is hydrogen, or a lower alkyl, lower alkynyl or arylgroup; and X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion; and mixtures thereof, and a carrier thereforpharmaceutically acceptable anion, wherein the fused aromatic rings oraryl groups of R ¹ , R ² , R or R′ may be substituted with up to twogroups selected from halo, hydroxy, loweralkoxy or di(loweralkyl)aminogroups; and a pharmaceutically acceptable carrier therefor.
 2. Thecomposition of claim 1 wherein said compound has the formula wherein Yis a 2-phenyl-2-oxoethyl group R is aryl.
 3. The composition of claim 21wherein said compound is 3-(2-phenyl-2-oxoethyl)thiazolium bromide oranother biologically acceptable salt thereofX is a halide, tosylate,methanesulfonate or mesitylenesulfonate ion.
 4. The composition of claim2 wherein said compound is a 3-(2-phenyl-2-oxoethyl)-4-methylthiazoliumbromide or another biologically acceptable salt thereof .
 5. Thecomposition of claim 2 wherein said compound is a3-(2-phenyl-2-oxoethyl)-4,5-dimethylthiazolium bromide or anotherbiologically acceptable salt thereof .
 6. The composition of claim 2wherein said compound is a 3-(2-phenyl-2-oxoethyl)-5-methylthiazoliumbromide or another biologically acceptable salt thereof .
 7. Thecomposition of claim 2 1wherein said compound is3-(2-phenyl-2-oxoethyl)-benzothiazolium bromide or another biologicallyacceptable salt thereofX is a halide ion.
 8. The composition of claim 1wherein Y is a 2-amino-2-oxoethyl group.
 9. The composition of claim 8wherein said compound is a 3-(2-amino-2-oxoethyl)-4-methylthiazoliumbromide or another biologically acceptable salt thereof .
 10. Thecomposition of claim 8 wherein said compound is a3-(2,-amino-2-oxoethyl)benzothiazolium bromide or another biologicallyacceptable salt thereof .
 11. The composition of claim 8 wherein saidcompound is a3-(2-amino-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)thiazolium bromide oranother biologically acceptable salt thereof .
 12. The composition ofclaim 1 wherein said compound is a 3-(2-methyl-2-oxoethyl)thiazoliumchloride or another biologically acceptable salt thereof .
 13. Apharmaceutical composition for administration to an animal to inhibitthe advanced glycosylation of a target protein within said animal ,comprising a pharmaceutically effective amount of a compound one or morecompounds selected from the group consisting of compounds of theformula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower)alkyl, (lower)acyloxy(lower)alkyl, or loweralkyl, or R¹ and R² together with their ring carbons may be form anaromatic fused ring; Z is hydrogen or an amino group; Y is hydrogen, ora group of the formula —CH₂C(═O)R wherein R is a lower alkyl, loweralkoxy, hydroxy, amino or an aryl group and wherein, when R is aryl, atleast one of R¹ and R ² is other than hydrogen and R ¹ and R ² are notpart of a un-substituted fused phenyl ring; or a group of the formula—CH₂R′ wherein R′ is hydrogen, or a lower alkyl, lower alkynyl, or arylgroup; and X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion; and mixtures thereof, pharmaceuticallyacceptable anion, wherein the fused aromatic rings or aryl groups of R ¹, R ² , R or R′ may be substituted with up to two groups selected fromhalo, hydroxy, loweralkoxy or di(loweralkyl)amino groups: and apharmaceutically acceptable carrier therefor.
 14. The composition ofclaim 13 wherein said compound has the formula wherein Y is a2-phenyl-2-oxoethyl group R is aryl.
 15. The composition of claim 1413wherein said compound is 3-(2-phenyl-2-oxoethyl)thiazolium bromide oranother biologically acceptable salt thereofX is a halide, tosylate,methanesulfonate or mesitylenesulfonate ion.
 16. The composition ofclaim 14 wherein said compound is a3-(2-phenyl-2-oxoethyl)4-methylthiazolium bromide or anotherbiologically acceptable salt thereof .
 17. The composition of claim 14wherein said compound is a3-(2-phenyl-2-oxoethyl)-4,5-dimethylthiazolium bromide or anotherbiologically acceptable salt thereof .
 18. The composition of claim 14wherein said compound is a 3-(2-phenyl-2-oxoethyl)-5-methylthiazoliumbromide or another biologically acceptable salt thereof .
 19. Thecomposition of claim 14 13wherein said compound is3-(2-phenyl-2-oxoethyl)-benzothiazolium bromide or another biologicallyacceptable salt thereofX is a halide ion.
 20. The composition of claim14 wherein Y is a 2-amino-2-oxoethyl group.
 21. The composition of claim20 wherein said compound is a 3-(2-amino-2-oxoethyl)-4-methylthiazoliumbromide or another biologically acceptable salt thereof .
 22. Thecomposition of claim 20 wherein said compound is a3-(2-amino-2-oxoethyl)benzothiazolium bromide or another biologicallyacceptable salt thereof .
 23. The composition of claim 20 wherein saidcompound is a3-(2-amino-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)thiazolium bromide oranother biologically acceptable salt thereof .
 24. The composition ofclaim 13 wherein said compound is a 3-(2-methyl-2-oxoethyl)thiazoliumchloride or another biologically acceptable salt thereof .
 25. A methodfor inhibiting the advanced glycosylation of a target protein comprisingcontacting the target protein with an effective amount of compositioncomprising a compound one or more compounds selected from the groupconsisting of compounds of the formula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower) alkyl, lower acyloxy(lower)alkyl, or loweralkyl, or R¹ and R² together with their ring carbons may be form anaromatic fused ring; Z is hydrogen or an amino group; Y is hydrogen, ora group of the formula —CH₂C(═O)—R wherein R is a lower alkyl, loweralkoxy, hydroxy, amino or aryl group; or a group of the formula —CH₂—R′wherein R′ is hydrogen, or a lower alkyl, lower alkynyl or aryl group;and X is a halide, rosylate, methanesulfonate or mesitylenesulfonateion; and mixtures thereof, and a carrier therefor pharmaceuticallyacceptable anion, wherein the fused aromatic rings or aryl groups of R ¹, R ² , R or R′ may be substituted with up to two groups selected fromhalo, hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 26. The methodof claim 25 wherein said compound has the formula wherein Y is a2-phenyl-2-oxoethyl group R is aryl.
 27. The method of claim 26 whereinsaid compound is a 3-(2-phenyl-2-oxoethyl)thiazolium bromide or anotherbiologically acceptable salt thereof .
 28. The method of claim 26wherein said compound is a 3-(2-phenyl-2-oxoethyl)-4-methylthiazoliumbromide or another biologically acceptable salt thereof .
 29. The methodof claim 26 wherein said compound is a3-(2-phenyl-2-oxoethyl)-4,5-dimethylthiazolium bromide or anotherbiologically acceptable salt thereof .
 30. The method of claim 26wherein said compound is a 3-(2-phenyl-2-oxoethyl)-5-methylthiazoliumbromide or another biologically acceptable salt thereof .
 31. The methodof claim 26 wherein said compound is a3-(2-phenyl-2-oxoethyl)-benzothiazolium bromide, or another biologicallyacceptable salt thereof .
 32. The method of claim 25 wherein Y is a2-amino-2-oxoethyl group.
 33. The method of claim 32 wherein saidcompound is a 3-(2-amino-2-oxoethyl)-4-methylthiazolium bromide oranother biologically acceptable salt thereof .
 34. The method of claim32 wherein said compound is a 3-(2-amino-2-oxoethyl)benzothiazoliumbromide or another biologically acceptable salt thereof .
 35. The methodof claim 32 wherein said compound is a3-(2-amino-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)thiazolium bromide oranother biologically acceptable salt thereof .
 36. The method of claim25 wherein said compound is a 3-(2-methyl-2-oxoethyl)thiazolium chlorideor another biologically acceptable salt thereof .
 37. A method fortreating diabetes or treating or ameliorating adverse sequelae ofdiabetes in an animal to inhibit the formation of advanced glycosylationendproducts of a target protein within said animal , said methodcomprising administering an a diabetes treating or adverse sequelae ofdiabetes treating or ameliorating effective amount of a pharmaceuticalcomposition, said pharmaceutical composition comprising a compound oneor more compounds selected from the group consisting of compounds of theformula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy (lower)alkyl, lower acyloxy(lower)alkyl, or loweralkyl or R^(‘)and R² together with their ring carbons may be form anaromatic fused ring; Z is hydrogen or an amino group; Y is hydrogen, ora group of the formula —CH₂C(═O)—R wherein R is a lower alkyl, loweralkoxy, hydroxy, amino or aryl group; or a group of the formula CH₂—R′wherein R′ is hydrogen, or a lower alkyl, lower alkynyl or aryl group;and X is a halide, tosylate, methanesulfonate or mesitylenesulfonateion; and mixtures thereof, and a pharmaceutically acceptable carriertherefor pharmaceutically acceptable anion, wherein the fused aromaticrings or aryl groups of R ¹ , R ² , R or R′ may be substituted with upto two groups selected from halo, hydroxy, loweralkoxy ordi(loweralkyl)amino groups.
 38. The method of claim 37 wherein saidcompound has the formula wherein Y is a 2-phenyl-2-oxoethyl group R isaryl.
 39. The method of claim 38 wherein said compound is3-(2-phenyl-2-oxoethyl)thiazolium bromide or another biologicallyacceptable has the formula wherein Y is a 2-phenyl- 2 -oxoethyl groupsalt thereof .
 40. The method of claim 38 wherein said compound is a3-(2-phenyl-2-oxoethyl)-4-methylthiazolium bromide or anotherbiologically acceptable salt thereof .
 41. The method of claim 38wherein said compound is a3-(2-phenyl-2-oxoethyl)-4,5-dimethylthiazolium bromide or anotherbiologically acceptable salt thereof .
 42. The method of claim 38wherein said compound is a 3-(2-phenyl-2-oxoethyl)-5-methylthiazoliumbromide or another biologically acceptable salt thereof .
 43. The methodof claim 38 wherein said compound is a3-(2-phenyl-2-oxoethyl)-benzothiazolium bromide or another biologicallyacceptable salt thereof .
 44. The method of claim 37 wherein Y is a2-amino-2-oxoethyl group.
 45. The method of claim 44 wherein saidcompound is a 3-(2-amino-2-oxoethyl)-4-methylthiazolium bromide oranother biologically acceptable salt thereof .
 46. The method of claim44 wherein said compound is a 3-(2-amino-2-oxoethyl)benzothiazoliumbromide or another biologically acceptable salt thereof .
 47. The methodof claim 45 wherein said compound is a3-(2-amino-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)thiazolium bromide oranother biologically acceptable salt thereof .
 48. The method of claim37 wherein said compound is a 3-(2-methyl-2-oxoethyl)thiazolium chlorideor another biologically acceptable salt thereof. .
 49. A method ofinhibiting the discoloration of teeth resulting from non-enzymaticbrowning in the oral cavity which comprises administration of an amounta teeth discloration inhibiting effective to inhibit the formation ofadvanced glycosylation endproducts amount of a composition comprising acompound one or more compounds selected from the group consisting ofcompounds of the formula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower)alkyl, lower acyloxy(lower)alkyl, loweracyloxy(lower)alkyl, lower acyloxy(lower)alkyl, or lower alkyl, or R¹and R² together with their ring carbons may be form an aromatic fusedring; Z is hydrogen or an amino group; Y is hydrogen, or a group of theformula —CH₂C(═O)—R wherein R is a lower alkyl, lower alkoxy, hydroxy,amino or aryl group; or a group of the formula CH₂—R′ wherein R′ ishydrogen, or a lower alkyl, lower alkynyl or aryl group; and X is ahalide, tosylate, methanesulfonate or mesitylenesulfonate ion; andmixtures thereof, and a pharmaceutically acceptable carrier therefor ananion, wherein said fused aromatic rings or aryl groups can besubstituted with up to two groups selected from halo, hydroxy,loweralkoxy or di(loweralkyl)amino groups.
 50. A compound of theformula:

wherein Y and Z are both amino groups and R¹ and R² are independentlyselected from the group consisting of hydrogen, hydroxy(lower)alkyl,lower alkyl, or R¹ and R² together with their ring carbons may be anaromatic fused ring; and X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion an anion.
 51. The compound according to claim 50which is a 2,3-diaminothiazolium mesitylenesulfonate .
 52. The compoundaccording to claim 50 which is a 2,3-diaminobenzothiazoliummesitylenesulfonate .
 53. A compound of the formula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower)alyl, lower acyloxy(lower)alkyl, or loweralkyl, or R¹ and R² together with their ring carbons may be an aromaticfused ring; Z is hydrogen or an amino group; Y is an alkynylmethylgroup; and X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion an anion.
 54. A compound of the formula:

wherein R¹ and R² are independently selected from the group consistingof hydrogen, hydroxy(lower)alkyl, lower acyloxy(lower)alkyl, or loweralkyl, or R¹ and R² together with their ring carbons may be form anaromatic fused ring; Z is hydrogen or an amino group; Y is a2-amino-2-oxoethyl group; and X is a halide, tosylate, methanesulfonateor mesitylenesulfonate ion an anion.
 55. The compound according to claim54 which is a 3-(2-amino-2-oxoethyl)-4-methylthiazolium bromide oranother biologically acceptable salt thereof .
 56. The compoundaccording to claim 54 which is a 3-(2-amino-2-oxoethyl)benzothiazoliumbromide or another biologically acceptable salt thereof .
 57. Thecompound according to claim 54 which is a3-(2-amino-2-oxoethyl)-4-methyl-5-(2-hydroxyethyl)thiazolium bromide oranother biologically acceptable salt thereof .
 58. A method of treatingor ameliorating kidney damage in an animal, said method comprisingadministering an kidney treating or ameliorating effective amount of apharmaceutical composition, said pharmaceutical composition comprisingone or more compounds selected from compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring: Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower lower alkoxy, hydroxy, amino or aryl group; ora group of the formula CH ₂ —R′ wherein R′ is hydrogen, or a loweralkyl, lower alkynyl or aryl group; and X is a pharmaceuticallyacceptable anion, wherein the fused aromatic rings or aryl groups of R ¹, R ² , R or R′ may be substituted with up to two groups selected fromhalo, hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 59. The methodof claim 58 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 60. The method of claim 58 wherein Z ishydrogen.
 61. The method of claim 58 wherein R is aryl.
 62. The methodof claim 61 wherein Z is hydrogen.
 63. The method of claim 61 whereinsaid compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4 -methylthiazolium. 64.The method of claim 61 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)- 4,5 -dimethylthiazolium.
 65. The method of claim 61 whereinsaid compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5 -methylthiazolium. 66.The method of claim 61 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)-benzothiazolium.
 67. The method of claim 58 wherein Y is a2-amino- 2 -oxoethyl group.
 68. The method of claim 58, comprisingtreating or preventing kidney damage in a human.
 69. A method oftreating or ameliorating damage to blood vasculature in an animal, saidmethod comprising administering an blood vasculature treating orameliorating effective amount of a pharmaceutical composition, saidpharmaceutical composition comprising one or more compounds selectedfrom compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 70. The method ofclaim 69 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 71. The method of claim 69 wherein Z ishydrogen.
 72. The method of claim 69 wherein R is aryl.
 73. The methodof claim 72 wherein Z is hydrogen.
 74. The method of claim 72 whereinsaid compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4 -methylthiazolium. 75.The method of claim 72 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)- 4,5 -dimethylthiazolium.
 76. The method of claim 72 whereinsaid compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5 -methylthiazolium. 77.The method of claim 72 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)-benzothiazolium.
 78. The method of claim 69 wherein Y is a2-amino- 2 -oxoethyl group.
 79. The method of claim 69, comprisingtreating or preventing damage to blood vasculature in a human.
 80. Amethod of improving the elasticity or reducing wrinkles of the skin ofan animal, said method comprising topically administering an skinelasticity or wrinkle reducing effective amount of a pharmaceuticalcomposition, said pharmaceutical composition comprising one or morecompounds selected from compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a biologically acceptable anion,wherein the fused aromatic rings or aryl groups of R ¹ , R ² , R or R′may be substituted with up to two groups selected from halo, hydroxy,loweralkoxy or di(loweralkyl)amino groups.
 81. The method of claim 80wherein X is a halide, tosylate, methanesulfonate or mesitylenesulfonateion.
 82. The method of claim 80 wherein Z is hydrogen.
 83. The method ofclaim 80 wherein R is aryl.
 84. The method of claim 83 wherein Z ishydrogen.
 85. The method of claim 83 wherein said compound is a 3-( 2-phenyl- 2 -oxoethyl)- 4 -methylthiazolium.
 86. The method of claim 83wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4,5-dimethylthiazolium.
 87. The method of claim 83 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 5 -methylthiazolium.
 88. The method ofclaim 83 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)-benzothiazolium.
 89. The method of claim 80 wherein Y is a2-amino- 2 -oxoethyl group.
 90. The method of claim 80 comprisingimproving the elasticity or reducing wrinkles of the skin of a human.91. A topical composition comprising one or more compounds selected fromcompounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy(lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ₁ and R ₂ together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula —CH ₂ R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a biologically acceptable anion,wherein the fused aromatic rings or aryl groups of R ¹ , R ² , R or R′may be substituted with up to two groups selected from halo, hydroxy,loweralkoxy or di(loweralkyl)amino groups; and a pharmaceuticallyacceptable carrier therefor suitable for topical administration.
 92. Thetopical composition of claim 91 wherein X is a halide, tosylate,methanesulfonate or mesitylenesulfonate ion.
 93. The topical compositionof claim 91 wherein Z is hydrogen.
 94. The topical composition of claim91, wherein, when R is aryl, at least one of R¹ and R ² is other thanhydrogen and R ¹ and R ² are not part of a un-substituted fused phenylring.
 95. The topical composition of claim 94 wherein Z is hydrogen. 96.The topical composition of claim 95 wherein R is aryl.
 97. The topicalcomposition of claim 96 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)thiazolium.
 98. The topical composition of claim 96 whereinsaid compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4 -methylthiazolium. 99.The topical composition of claim 96 wherein said compound is a 3-( 2-phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 100. The topicalcomposition of claim 96 wherein said compound is 3-( 2 -phenyl- 2-oxoethyl)- 4,5 -dimethylthiazolium bromide.
 101. The topicalcomposition of claim 96 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)- 5 -methylthiazolium.
 102. The topical composition of claim96 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)-benzothiazolium.
 103. The topical composition of claim 96wherein Y is a 2-amino- 2 -oxoethyl group.
 104. The topical compositionof claim 103 wherein said compound is a 3-( 2 -amino- 2 -oxoethyl)- 4-methylthiazolium.
 105. The topical composition of claim 103 whereinsaid compound is a 3-( 2,-amino- 2 -oxoethyl)benzothiazolium.
 106. Thetopical composition of claim 103 wherein said compound is a 3-( 2-amino- 2 -oxoethyl)- 4 -methyl- 5 -( 2 -hydroxyethyl)thiazolium.
 107. Amethod of treating or ameliorating hypertension in an animal, saidmethod comprising administering an hypertension treating or amelioratingeffective amount of a pharmaceutical composition, said pharmaceuticalcomposition comprising one or more compounds selected from compounds ofthe formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically or biologicallyacceptable anion, wherein the fused aromatic rings or aryl groups of R ¹, R ² , R or R′ may be substituted with up to two groups selected fromhalo, hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 108. Themethod of claim 107 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 109. The method of claim 107 wherein X is ahalide ion.
 110. The method of claim 107 wherein Z is hydrogen.
 111. Themethod of claim 107 wherein R is aryl.
 112. The method of claim 111wherein Z is hydrogen.
 113. The method of claim 111 wherein saidcompound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4 -methylthiazolium.
 114. Themethod of claim 111 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)- 4,5 -dimethylthiazolium.
 115. The method of claim 111wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 116. The method of claim 111 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 117. The method of claim107 wherein Y is a 2-amino- 2 -oxoethyl group.
 118. The method of claim107, comprising treating or ameliorating hypertension in a human.
 119. Amethod of treating or ameliorating retinopathy in an animal, said methodcomprising administering an retinopathy treating or amelioratingeffective amount of a pharmaceutical composition, said pharmaceuticalcomposition comprising one or more compounds selected from compounds ofthe formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 120. The method ofclaim 119 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 121. The method of claim 119 wherein X is ahalide ion.
 122. The method of claim 119 wherein Z is hydrogen.
 123. Themethod of claim 119 wherein R is aryl.
 124. The method of claim 123wherein Z is hydrogen.
 125. The method of claim 123 wherein saidcompound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4 -methylthiazolium.
 126. Themethod of claim 123 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)- 4,5 -dimethylthiazolium.
 127. The method of claim 123wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 128. The method of claim 123 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 129. The method of claim120 wherein Y is a 2-amino- 2 -oxoethyl group.
 130. The method of claim120, comprising treating or ameliorating retinopathy in a human.
 131. Amethod of treating damage to lens proteins in an animal, said methodcomprising administering an lens damage treating effective amount of apharmaceutical composition, said pharmaceutical composition comprisingone or more compounds selected from compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 132. The method ofclaim 131 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 133. The method of claim 131 wherein Z ishydrogen.
 134. The method of claim 131 wherein R is aryl.
 135. Themethod of claim 134 wherein Z is hydrogen.
 136. The method of claim 134wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4-methylthiazolium.
 137. The method of claim 134 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 138. The methodof claim 134 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 139. The method of claim 134 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 140. The method of claim131 wherein Y is a 2-amino- 2 -oxoethyl group.
 141. The method of claim131, comprising treating damage to lens proteins in a human.
 142. Amethod of treating or ameliorating peripheral neuropathy in an animal,said method comprising administering an neuropathy treating orameliorating effective amount of a pharmaceutical composition, saidpharmaceutical composition comprising one or more compounds selectedfrom compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 143. The method ofclaim 142 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 144. The method of claim 142 wherein Z ishydrogen.
 145. The method of claim 142 wherein R is aryl.
 146. Themethod of claim 145 wherein Z is hydrogen.
 147. The method of claim 145wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4-methylthiazolium.
 148. The method of claim 145 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 149. The methodof claim 145 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 150. The method of claim 145 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 151. The method of claim142 wherein Y is a 2-amino- 2 -oxoethyl group.
 152. The method of claim142, comprising treating or ameliorating peripheral neuropathy in ahuman.
 153. A composition adapted for ocular administration comprisingone or more compounds selected from compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy(lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ₁ and R ₂ together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula —CH ₂ R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups; and apharmaceutically acceptable carrier therefor suitable for topicaladministration.
 154. The ocular composition of claim 153 wherein X is ahalide, tosylate, methanesulfonate or mesitylenesulfonate ion.
 155. Theocular composition of claim 153 wherein X is a halide ion.
 156. Theocular composition of claim 153 wherein Z is hydrogen.
 157. The ocularcomposition of claim 153, wherein, when R is aryl, at least one of R¹and R ² is other than hydrogen and R ¹ and R ² are not part of aun-substituted fused phenyl ring.
 158. The ocular composition of claim157 wherein Z is hydrogen.
 159. The ocular composition of claim 158wherein R is aryl.
 160. The ocular composition of claim 158 wherein saidcompound is a 3-( 2 -phenyl- 2 -oxoethyl)thiazolium.
 161. The ocularcomposition of claim 158 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)- 4 -methylthiazolium.
 162. The ocular composition of claim158 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4,5-dimethylthiazolium.
 163. The ocular composition of claim 158 whereinsaid compound is 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazoliumbromide.
 164. The ocular composition of claim 158 wherein said compoundis a 3-( 2 -phenyl- 2 -oxoethyl)- 5 -methylthiazolium.
 165. The ocularcomposition of claim 158 wherein said compound is a 3-( 2 -phenyl- 2-oxoethyl)-benzothiazolium.
 166. The ocular composition of claim 153wherein Y is a 2-amino- 2 -oxoethyl group.
 167. The ocular compositionof claim 166 wherein said compound is a 3-( 2 -amino- 2 -oxoethyl)- 4-methylthiazolium.
 168. The ocular composition of claim 166 wherein saidcompound is a 3-( 2,-amino- 2 -oxoethyl)benzothiazolium.
 169. The ocularcomposition of claim 166 wherein said compound is a 3-( 2 -amino- 2-oxoethyl)- 4 -methyl- 5 -( 2 -hydroxyethyl)thiazolium.
 170. Thecomposition of claim 1, wherein said compounds comprise up to 10% of thecomposition.
 171. The composition of claim 13 wherein Z is hydrogen.172. The composition of claim 14 wherein Z is hydrogen.
 173. Thecomposition of claim 13 wherein said compound is 3-( 2 -phenyl- 2-oxoethyl) 4 -methylthiazolium bromide.
 174. The composition of claim 13wherein said compound is 3-( 2 -phenyl- 2 -oxoethyl)- 4,5-dimethylthiazolium bromide.
 175. The composition of claim 13 whereinsaid compound is 3-( 2 -phenyl- 2 -oxoethyl)- 5 -methylthiazoliumbromide.
 176. The composition of claim 13 wherein said compound is 3-( 2-amino- 2 -oxoethyl)- 4 -methylthiazolium bromide.
 177. The compositionof claim 13 wherein said compound is 3-( 2 -amino- 2-oxoethyl)benzothiazolium bromide.
 178. The composition of claim 13wherein said compound is 3-( 2 -amino- 2 -oxoethyl)- 4 -methyl- 5 -( 2-hydroxyethyl)thiazolium bromide.
 179. The composition of claim 13wherein said compound is a 3-( 2 -methyl- 2 -oxoethyl)thiazoliumchloride.
 180. The method of claim 37, comprising treating diabetes ortreating or ameliorating adverse sequelae of diabetes in a human. 181.The method of claim 37 wherein Z is hydrogen.
 182. The method of claim38 wherein Z is hydrogen.
 183. A method of treating or amelioratingcataracts in an animal, said method comprising administering an lensdamage treating or ameliorating effective amount of a pharmaceuticalcomposition, said pharmaceutical composition comprising one or morecompounds selected from compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 184. The method ofclaim 183 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 185. The method of claim 183 wherein Z ishydrogen.
 186. The method of claim 183 wherein R is aryl.
 187. Themethod of claim 186 wherein Z is hydrogen.
 188. The method of claim 186wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4-methylthiazolium.
 189. The method of claim 186 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 190. The methodof claim 186 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 191. The method of claim 186 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 192. The method of claim183 wherein Y is a 2-amino- 2 -oxoethyl group.
 193. The method of claim183, comprising treating or ameliorating damage to lens proteins in ahuman.
 194. A method of treating or ameliorating damage to a tissuecaused by contact with elevated levels of reducing sugars in an animal,said method comprising administering an treating or amelioratingeffective amount of a pharmaceutical composition, said pharmaceuticalcomposition comprising one or more compounds selected from compounds ofthe formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 195. The method ofclaim 194 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 196. The method of claim 194 wherein Z ishydrogen.
 197. The method of claim 194 wherein R is aryl.
 198. Themethod of claim 197 wherein Z is hydrogen.
 199. The method of claim 197wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4-methylthiazolium.
 200. The method of claim 197 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 201. The methodof claim 197 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 202. The method of claim 197 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 203. The method of claim194 wherein Y is a 2-amino- 2 -oxoethyl group.
 204. The method of claim194, comprising administering the compound intraperitoneally.
 205. Amethod of treating or ameliorating stroke in an animal, said methodcomprising administering a stroke treating or ameliorating effectiveamount of a pharmaceutical composition, said pharmaceutical compositioncomprising one or more compounds selected from compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 206. The method ofclaim 205 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 207. The method of claim 205 wherein Z ishydrogen.
 208. The method of claim 205 wherein R is aryl.
 209. Themethod of claim 208 wherein Z is hydrogen.
 210. The method of claim 208wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4-methylthiazolium.
 211. The method of claim 208 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 212. The methodof claim 208 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 213. The method of claim 208 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 214. The method of claim205 wherein Y is a 2-amino- 2 -oxoethyl group.
 215. A method of treatingor ameliorating osteoarthritis in an animal, said method comprisingadministering a osteoarthritis treating or ameliorating effective amountof a pharmaceutical composition, said pharmaceutical compositioncomprising one or more compounds selected from compounds of the formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 216. The method ofclaim 205 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 217. The method of claim 205 wherein Z ishydrogen.
 218. The method of claim 205 wherein R is aryl.
 219. Themethod of claim 208 wherein Z is hydrogen.
 220. The method of claim 208wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4-methylthiazolium.
 221. The method of claim 208 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 222. The methodof claim 208 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 223. The method of claim 208 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 224. The method of claim205 wherein Y is a 2-amino- 2 -oxoethyl group.
 225. A method ofincreasing red blood cell deformability in an animal, said methodcomprising administering a red blood cell deformability increasingeffective amount of a pharmaceutical composition, said pharmaceuticalcomposition comprising one or more compounds selected from compounds ofthe formula:

wherein R ¹ and R ² are independently hydrogen, hydroxy (lower)alkyl,lower acyloxy(lower)alkyl, or lower alkyl, or R ¹ and R ² together withtheir ring carbons form an aromatic fused ring; Z is hydrogen or anamino group; Y is hydrogen, a group of the formula —CH ₂ C(═O)—R whereinR is a lower alkyl, lower alkoxy, hydroxy, amino or aryl group; or agroup of the formula CH ₂ —R′ wherein R′ is hydrogen, or a lower alkyl,lower alkynyl or aryl group; and X is a pharmaceutically acceptableanion, wherein the fused aromatic rings or aryl groups of R ¹ , R ² , Ror R′ may be substituted with up to two groups selected from halo,hydroxy, loweralkoxy or di(loweralkyl)amino groups.
 226. The method ofclaim 205 wherein X is a halide, tosylate, methanesulfonate ormesitylenesulfonate ion.
 227. The method of claim 205 wherein Z ishydrogen.
 228. The method of claim 205 wherein R is aryl.
 229. Themethod of claim 208 wherein Z is hydrogen.
 230. The method of claim 208wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 4-methylthiazolium.
 231. The method of claim 208 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)- 4,5 -dimethylthiazolium.
 232. The methodof claim 208 wherein said compound is a 3-( 2 -phenyl- 2 -oxoethyl)- 5-methylthiazolium.
 233. The method of claim 208 wherein said compound isa 3-( 2 -phenyl- 2 -oxoethyl)-benzothiazolium.
 234. The method of claim205 wherein Y is a 2-amino- 2 -oxoethyl group.